Photographic developer



Patented Nov. 10, 1936 UNITED STATES PATENT OFFICE manns, Wolten-Kreis Bitterield, Germany,

signors to Agia Ansco Corporation, Binghamton, N. If a corporation of New York No Drawing. Application May 17, 1935, Serial No. 21,976. In 6 may June 9, 1934 1 Claims. (01. ss-ss) Our present invention relates to photographic developers.

One of its objects is a group of new photographic developers. Another object is a group 01' photographic developers which can be used without the addition of alkali. Still another object is a group'of photographic developers'which can be used with or without the addition oi alkali. Further objects will be seen from the detailed specification following hereafter.-

For developing photographic silver halide emulsions alkaline developers are generally used. An exception is amidol, which can be made up into a developer only with suiflte. Amidol, however, has various disadvantages. 0n the one hand a developer prepared with it is easily susceptible to oxidation on exposure to air and is therefore oi poor stability; furthermore amidol becomes intensely colored when it is brought into contact with alkali.

The present invention provides developers which. like amidol, develop in absence of alkali but have various advantages over this substance. A developer in accordance with the invention comprises an amino-substituted 2-methylaminophenol, for example, .4-amino-2-methylaminophenol, 5-dimethylamino-2-methylamino-phenol, 4-amino-6-methyl-2-methylamino phenol or 6- amino-4-methyl-z-methylamino-phenol. Such products may be obtained, for example, by fission of amino substituted Z-methyI-benzoxazole di-' methyl sulfates with caustic soda solution and subsequent saponiilcation oi the acetyl compound by means of hydro-chloric acid. The 2-methylamino-phenols substituted by an amino-group or by a dialkylamino-group excel amidol in particular in the speed of development.

It is possible by introducing a further alkylgroup or a halogen atom to remove the property, possessed by amidol, of becoming intensely colored immediately on contact with alkali.

Finally, the last named di-substituted bodies have, when the substituents are in suitable positions, the remarkable advantage that they are very insensitive towards atmospheric oxidation and therefore yield developers which are stable for long periods.

The following are examples of some developers in accordance with the present invention:

. E's-ample 1 200 cc. 0! water 5 grams atsodium suliite 1 gram ofa-dimethylamino-z-methylaminophgnd fl' T Example 2 200 cc. of water 5 grams of sodium sulflte 1 gram oi 4-amino-6-methyl-2-methylamino-phenol.

Example 3 200 cc. of water 5 grams of sodium sulflte m 1 gram of 6-amino-4-methyl-2-methylamino-phenol.

Example 4 What we claim is: 1

1. A photographic developer including va. 2- methyiaminophenol containing in its nucleus a radical selected from the group consisting of amino groups and dialkylamino groups.

2. A photographic developer including a 2- methylaminophenol' containing in its nucleus a radical selected from thegroup consisting 01' amino groups and dialkylamino groups without an alkali.

3. A photographic developer including a 2- methylaminophenol containing in its nucleus besides a 'radical selected from the group consisting of amino groups and dialkylamino groups a radical selected from the group consisting of halide and alkyl.

4. A photographic developer including a 2- methylaminophenol containing in its nucleus be- 40 sides a radical selected from the group consisting of amino groups and dialkyl'amino groups a radical selected from the group consisting of halide, alkyl and an alkali.

5. A photographic developer including 5-dimethylamino-2-methylamino-phenol.

6. A photographic developer including 4-amino-B-methyl-2-methylamino-phenol.

7. A photographic developer including 6-amino-4--methyl-2-methylamino-phenol.

WILHEIM SCHNEIDER. GUSTAV WIIMANNB. 

